#help-0
1 messages · Page 686 of 1
nope im quite new to further trigo
It’s the relation of sine and cosine in a right triangle
If you were to try and use a calculator, you’d get the same values!
ok, ill try it out
Make sure that if for example you want the sin of pi/6
The cosine is 2pi/6
The identity could also be written as:
sin(pi/2-x)=cos(x)
shockingly, it was discovered that pi is not the same as pi/2
yea
So without further ado, @hollow pelican
You may replace the cos(pi/2-theta) with just sin(theta)!
From there, you’ve got a pretty simple trigonometric equation
ok
Only now the question is, is there another solution?
I am not sure
hmm is it
Nope, pay attention.
don’t barge in like that bud, haven’t you noticed that we’re talking here?
For you,
You might have never heard of the formula, sin(pi-x)=sin(x)
Use that to find the second solution, and you’re set!
okay
That should be all, is there anything else?
no, thanks btw
Anytime.
is this channel free??
it's true for any positive real number
@dawn wraith oh sorry didn't noticed
It’s fine.
yes
ok thanks
if in conditional probability $$ P(B|A) = \frac{P(B) and P(A)}{P(B)} $$
and $$ P(B) = \frac{#Events}{Sample Space of A} $$
Since P(B) is being multiplied by P(A) and that is being divided out of P(A) doesn't that mean
$$ P(B|A) = P(B)?$$
Nerdy_Coder
Compile Error! Click the
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sorry let me fix that(but still answer my question)
if in conditional probability $$ P(B|A) = \frac{P(B and A)}{P(B)} $$
and $$ P(B) = \frac{#Events}{Sample Space of A} $$
Since P(B) is being multiplied by P(A) and that is being divided out of P(A) doesn't that mean
$$ P(B|A) = P(B)?$$
If A and B are independent, then yes, conditional probability is just P(B)
Nerdy_Coder
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reaction for more information.
(You may edit your message to recompile.)
oh
I see that's why it just doesn't say P(B)
because if they aren't mutaully exclusive....
Yeah..
then it's P(B)-P(A and B) right?
don't leave spaces between the $ and the code. use \text{} for the text and you can use \cap for the intersection sign.
There's channels to test the bots
Ahh makes sense
thanks
seeing as to how you find the roots of a polynomial by setting it to 0, does that mean the roots are the x-intercepts?
yes..
ok
obviously
sorry my book is really shitty and didnt tell me that
roots, zeroes, x-intercepts are all equivalent
they're teaching everything backwards and in the wrong order wtf
they show me a method in one lesson without explanation, then I have to spend an hour searching it up and learning it myself via youtube, only for them to explain it a couple lessons later
they "Taught" me synthetic division before long division of polynomials and i had to take like an hour to figure out wtf synthetic division was
and then they explain how to do it thoroughly like 4 lessons later
@glass lichen so root is just another word for x-intercept? or does it server another purpose
$$text{Also use Ration Root(or Zero) Theorim as }\frac{p}{q} text{Helps you find the rational roots of ANY polynomial P = Leading Coefficent Q = Coefficent of Constant}$$
Nerdy_Coder
Nerdy_Coder
$$\text{Also use Rational Root(or Zero) Theorim as }\frac{p}{q} \text{Helps you find the rational roots of ANY polynomial P = Leading Coefficent Q = Coefficent of Constant}$$
$$\text{Also use Rational Root(or Zero) Theorim as }\frac{p}{q} \text{Helps you find the rational roots of ANY polynomial P = Leading Coefficent Q = Coefficent of Constant}$$
Nerdy_Coder
sigh
$$\text{Also use Rational Root(or Zero) Theorim as }\frac{p}{q}
\text{Helps you find the rational roots of ANY polynomial P = Leading Coefficent Q = Coefficent of Constant}$$
Nerdy_Coder
there we go
can you stop spamming?
noooo
Also use Rational Root (or Zero) Theorim as $\frac{p}{q}$ Helps you find the rational roots of ANY polynomial P = Leading Coefficent Q = Coefficent of Constant
TheMane3
there @native temple
is not what rrt states
oh thanks
rational root therim
the acronym for rational root theorem
oh ok
A polynomial P(x) has a rational root when $x=\pm\frac{p}{q}$, were q is a factor of the constant term and p is a factor of the leading coefficient
Mosh
yes
"The roots of a polynomial are those values of the variable that cause the polynomial to evaluate to zero", wouldn't that just be what you put into f(x)? so in f(3), 3 is the root? the only value you can put in f(x) to make it equal to zero is f(0) though, right?
Oh I messed that up
if f(3)=0, then yes
ohhh
Turn fractions into decimal numbers and sort results into exact decimals or periodic decimals with the calculations please
f(3) would only ever equal zero if a, b, and c were 0 though :/
I don't even understand the question
$f(x)=(x-3)(x-1)$, clearly $f(3)=0$
Mosh
likewise, clearly f(0)=3 in that case (coincidence it ended up being 3 and 0 swapping)
https://www.britannica.com/science/rational-root-theorem @warped phoenix
Rational root theorem, in algebra, theorem that for a polynomial equation in one variable with integer coefficients to have a solution (root) that is a rational number, the leading coefficient (the coefficient of the highest power) must be divisible by the denominator of the fraction and the
How do I know if x is approaching negative infinity and positive infinity?
It says to evaluate the function using a large negative and large positive number
but like...what's the threshold.
just check end behaviours..
what is that
this is the function
they evaluate using -1000, and 1000, should I always use those numebrs?
yeah, end behaviour is dominated by the leading term
so it's the same thing that happens to y=x^3
which is an odd power and positive co-efficient, so x->inf means y-> inf x-> -inf means y->-inf
the highest power term
x^3 is the leading term..
x^3 is positive if x is positive..
right
"Seeing as to how x isnt negative"
that means it approaches pos. infinity right?
but if x was negative, x --> -infinity ?
yes, for odd powers one end is +inf and the other is -inf
because you have to evaluate the function with both a negative and positive number, got it
when they say "large pos/neg. number", what's the threshold for that?
anything above 1000?
literally any big number
100's pretty big..
then use 100
ohhhhhhhhhhhhhhhhhhh
😄
if x approaches negative or positive infinity, f(x) [so y basically] HAS to follow whatever one x is approaching right?
if x --> + inf., y --> + inf.
you said that before i think but i just wanted to make sure
no
end behaviour is reduced down to the same end behaviour as $y=\pm x^2$ and $y=\pm x$
Mosh
ie the leading term's degree's parity and leading co-efficient's sign
even and oddness of an integer
??
yeah, what about it?
how do i know how far right and far left to go
the domain of a polynomial is R...
oh
domain is the input space
wdym by input space
the space of values you can put into the function
you should've learned domain as one of the 1st things..
LOL thats the first time im hearing this word (theres the shitty alg 2 book doing its work again)
so its what you substitute for x?
in other words, it's all possible values you can substitute for x. in this case, all real numbers from -infinity to infinity
ohh
$D_f=\mathbb{R}$ for any polynomial f
Mosh
some functions for example, like f(x) = 1/x , won't let you put in x=0
so its domain would be all real numbers except 0.
does that mean domain of a function = real numbers @glass lichen
no
oh whats the f
"any polynomial f"
ah so domain of a polynomial = real numbers
yes
@finite spindle oh so the only two types of domains can be all real numbers, and all real numbers except 0?
No, clearly not
no, that was just one simple example
for example the function f(x) = 1/(3-x) cannot have x=3
oh ok, wait, so if x MAKES the denominator equal 0 then you exclude it
oh ok
right
for example yeah
ahh
$f(x)=\ln(x)\implies D_f=(0,\infty )$
Mosh
what's ln
natural log
(what's that 😅 )
anyway, back to the regular question...?
Log but with e
Question: What about a polynomial that's a root? Like $f(x) = x^{1/2}$, that technically has a complex domain, unless I'm just over thinking it
Mosh
ok, so, if the domain = any real number, basically what you're saying is I can choose how far left or right the graph goes?
after it hits the x int. ofc
yes, so long as the graph shows the intercepts / important features
ohhhhhhhhhhhhhhhhhhh
awesome
why are all of you better teachers than a multi-million dollar company's online schooling program....LOL
yeah, sqrt(x) isnt a monomial, since it's not a non-neg integer power dldh
likewise with 1/x
dldh06
$p(x)=\sum_{i=0}^n a_ix^i$ is polynomials of degree n
Mosh
Ah, whole numbers, makes sense
yeah
obviously you can write the binomial series for sqrt(x) and represent sqrt(x) as a poly
but sqrt(x) itself is not a monomial
are you supposed to learn long division with polynomials before you learn synthetic division?
technically yes, synthetic is the shortcut
welp my book did it the other way around 🥴
Can someone explain how they found the value of X and T
I'm particularly interested to know how they ended up on the hyperbolic functions
The characteristic equation is, for the first one,
r^2 + n^2 = 0
r^2 = -n^2 = (in)^2
r = in or r= -in, with i^2 = -1
With those conditions, they applied a formula which is the solution of the differential equation when solutions of characteristic equation are complex numbers
yes but you can do some works to get cosh and sinh
since cosh =( e^x + e^-x)/2
wait no
no I do not xD
ohh I see
But isn't that an additional burden
why not let it stay as cos and sin
It depends of the exercise, it can simplify calculation
hmm
You only have cosh and sinh, instead of exp and cos and sin
its much better for calculation
I saw physics exercise where we needed to use cosh and sinh
np
i just started using matlab, and i came accross this
[J, grad] = lrCostFunction(theta_t, X_t, y_t, lambda_t);
im not sure what this notation means
Which part?
theta_t = [-2; -1; 1; 2];
X_t = [ones(5,1) reshape(1:15,5,3)/10];
y_t = ([1;0;1;0;1] >= 0.5);
lambda_t = 3;
[J, grad] = lrCostFunction(theta_t, X_t, y_t, lambda_t)
Oh
is it that the function on the rhs produces two outputs
and J is the first and grad is the second?
Yes, exactly
mb i thought [J, grad] was a matrix but i wasnt thinking straight
Stores outputs of function into variable named "J" and "grad" respectively
pretend that is a parallelogram, would those to corners be the same
those two angles
yes? no?
yeah cos the sides are parallel right
algebra then triple angle
Umm what?
Gonna need a better question than "what?"
they did algebra... then did triple angle
I understand they used triple angle formula with sin
But i don't understand how they used it with cos
Can anyone teach me how to divide nos with cancelling them out
Cos3x = 4cos³x -3 cosx
But here we have 4cos²x-3cosx
How do they do it?
@glass lichen
typo
Where
How did they get
Cos(3-4 cos² t)
simplifiying with algebra
I don't understand i am sorry
have you done algebra before?
What formula did they use?
Can u give me an example of what they used?
Mosh
wah i was typing :C
@balmy thistle yeah, I saw that, go ahead.
hi ive got a few questions for an upcoming oral exam.
- whats the argument of sine and cosine?
- are there implicite functions you cant transform into explicite functions without information being lost? name examples.
- why is it useful to translate implicite into explicite forms?
thank you in advance 🙂
hmm is it supposed to be the answer for that exam?
no for self test
are these the questions on the exam or designated practice questions?
practice questions, i dont have the exam questions they are in 3 weeks from today
and i wont ask them here lol
Ok, so post your explanations/answers and someone can read it and comment on it
i srsly dont know the answers to it thats why i asked here to memorize them 😦
Memorizing answers is not the best way to study
but these questions are knowledge questions only o:
It's based on your own knowledge, not others
i googled already and found no answer thats why i came here in search of help 😦
It also helps if you spelled "sine" and "cosine" properly too
im from russia sorry for my english
Why quick?
I have an exam in a hour
?
The trig part looks wrong
Because it's sin(5x)
Isnt the integral of sin ( - cos x)
hey what's up, can you help me solve this?
9x - 7i > 3 (3x - 7u)
Channel busy
4x - cos 5x
Also use u sub
?
For this
Do u know the ans
We havent learned u sub
Google it
,w integral (4 + sin 5x)
That's what you said the answer key said
Use u sub for the trig part
Idk how to
Google it. You can learn the concept in like 10 minutes rather than have someone explain it for an hour
$u=5x\implies \dd{u}=5\dd{x}$
Mosh
?
Mosh just showed you u sub
have you done integrals of trig before...?
Yh
so you can integrate sin(x)?
Literally, if you don't understand the concept, and this pointless back and forth of you not understanding and people trying to explain, because you apparently have less than an hour, as you stated, Google u sub and watch videos on it
Yeah
- cos x
+c but yeah
Yeah
and yeah, google u-sub if you werent taught it..
or just ask what differentiates to sin(5x)
I dnt have time to learn a new concept now
well I doubt it's new given you're being asked about it...
so it must've been taught.
I doubt that, but anyway
Bruh
just google u-sub or reverse chain rule
Yeah so what do i do with that
with what?
I was just seeing if you at least knew how to integrate trig.
Bro
You've already been told it's u-sub
I need help solving the problem
and I helped you
With what
I did the u-sub part for you...
Asking me how to integrate sin
$u=5x\implies \dd{u}=5\dd{x}$
Mosh
That's u-sub
How do i apply it to the question
do the sub...
This is exactly what I mean by the pointless back and forth conversation of a concept you don't understand
I just want to know why its over 5
$\int \sin(5x)\dd{x}=\int\frac{1}{5}\sin(u)\dd{u}$
Mosh
+c, yes
You’re basically asking what’s
1/0^(1/0)
,help
A brief description and guide on how to use me was sent to your DMs!
Please use ,list to see a list of all my commands, and ,help cmd to get detailed help on a command!
this is what i was solving
a new number that I call z
So z to the zth power
yes
That should be it?
but what is z^z
Im aware z:=1/0
What does it mean when you raise something to the zth?
but by your construction it's just z^z
wdym?
You defined zed to be the number 1/0
yes
I do not know how to calculate a number in which is raised to that power
Only you can, for the reason that you defined the number itself
ok what happens when you have a 0th root
no clue, 0th root doesnt exist in standard math
Impossible, it’s like raising it to the power of something that is divided by 0
since 1/0 is an undefined object, you are giving it a definiton and thus need to define 0th root
Smart words that he said^
However also in your construction you have that 1=0
Is someone free here
this is all i have
I need help
That’s also true, it’s a contradiction.
Channel occupied, sorry.
$\frac{z}{z}=1, \forall z\neq 0$
Mosh
where?
z/z = 0 on your ss, however z/z = 1 since z isnt 0
Anything that you divide by itself will result in the number 1
anything non-zero
Yeah, obviously
and got 0
Which means you’ve got a contradiction
but can z be treated as non-zero?
holy
z is your number
I dont give a fuck about z
Your system that includes z looks to be equipped with operations from the real numbers, thus z/z=1
yeah, so you showed 1=0 in your system
since you are using facts about rational/real numbers
either z acts as 0 or as z
Hold up bud you’ve gone a step forward
what?
wheel algebra moment 
what could i do?
It's your system
This is like JK Rowling asking a random person to write the next Harry Potter
i mean i could say 0/0 = 1 but thats sounds very wrong
oh and z=1/0 means perfect sense...
Well, your system, your rules.
Go ahead and define it, it’ll hopefully fix the contradiction
Good!
Yeah, this is why 1/0 stays undefined
XD
cause assuming it is defined causes things to break
or i could just say that z is not non-zero
so z=0
no if z is not-non zero it just means non-zero is a set of numbers
Ugh
Im gonna say this bluntly: you are trying to define a system, it makes no sense to be asking other people on how the system works.
well im trying to see if the system works
it doesnt
cause you have simply taken the real numbers and added a new element in without redefining the operations.
- and * you're using act on R, not R w/ {z}
wait the 0th root of 1 is 1
i guess
a) sine rule
because I've tried the sin rule
angle A is 51.1
but if that's 51.1
it means the angle on th eother side is obtuse
and since it's isosceles
that would make two angles obtuse?
in a triangle
due to the identity
sin(180 - x) = sin(x) existing
piece of cake
Okay, practical question.
I have a set of products that sell at a known velocity.
I represent this velocity as a decimal of capacity in slots.
For example, Product A sells 0.1 slots per day. After 10 days it will sell through 1 slot.
A store has a set positive integer number of slots. 23, for example.
I can set the quantity of products in a store as a positive integer number of slots.
I want to set the slot quantity for each product in such a way as the minimum days of any individual product is as high as possible.
Sample set: A: 0.1 slots/day, B: 0.25 slots/day, C: 0.1 slots/day. D: 0.55 slots/day, E: 0.75 slots/day
Slot Capacity: 27
similar triangles
Wait would the second one be h?
ASA or SSS rules
just a hint that all those right triangles, the two triangles and the entire triangle itself, are similar to each other
Still a little confused
If you can, could you maybe explain how to do one of these problems?
ok first can you orientate each triangle in the figure such that they look similar?
and then the last one?
FDJ
wrong side order, since you did each in (shorter side, longer side, hypotenuse)
just apply that to the triangle you named
ok now, pick two triangles that include side j, and include side g, to answer the first question
We can use FJD and GED
DFJ* (remember that side order)
Ah ya
now, use this property of similar triangles: (chosen side of 1st triangle/same side of 2nd triangle) = (another chosen side of 1st triangle/same other side of 2nd triangle)
for example, you can set d/j = e/f
j/d=d/g?
Second one then is h?
Is it ok if I show 2 more
sure
kk
yes
yea
Could someone explain me this step?
I know it should give -0,4, but that's not the issue. How do you even get the 0,4?
,calc 1/2.5
Result:
0.4
But it should be -0.4
,calc (1/10)^(-1/2.5)
Result:
2.5118864315096
Yep I know that is wrong xd
Thank you
hey guys, i have a differential geometry question but i figured it could be a little advanced so i asked in topology-and-geometry, it's an exercise my professor solved that i didn't get, can anybody take a look?
thank you!
If you divide sqrt(2) on both sides
You will notcie a very particular patterns
sin(pi/4)=cos(pi/4)=1/sqrt(2)
Now substitute this into
sin(x)/sqrt(2)+cos(x)/sqrt(2)=1
lemme absorb what u said
pls elaborate this i have no clue as how we came here
Ok dont focus on that too much
are you clear on this?
yup
So we can rewrite the equation as sin(x)sin(pi/4) + cos(x)tsqrt(2)=1
i think i got it
Yeah
Basically this is a method of solving equations in the form asin(x)+bcos(x)=c
im good to go
yea ik im doing qs related to that only
mind go poof at times disables me to think about simple algebra at times
Well if you are interested, the first to doing that is dividing both sides by sqrt(a^2+b^2)
And the steps later on are just what we did
isnt that used to find r
like
Yes kind of
The idea is that we want to convert it into sin(x +/- y) or cos(x +/- y)
r=(a^2 + b^2)^1/2
yes man got it
thenks
...
@rigid smelt bruh
im getting wrong ans 😭
i tried this approach as well
for y = kf(x), the function is stretched away from the x axis if k > 0, compressed towards the x-axis if 0 < k < 1, and reflected across the x-axis if k > 0, right?
just to make sure im saying that right
if 0<k<1, the function is compressed, if k > 1, the function is stretched away from the x-axis, and it is reflected over the x axis if k < 0
ah ok
TheMane3
why do you shift the graph to the right two units when inside the parenthesis the 2 is negative? @queen wigeon
shouldn't it be moved two units to the left since f(x + k) is shifted to the right whereas f(x - k) is shifted to the left?
hello
i have some question it is not in math but i hope someone can help me :/
its on german hope someone you unserstand with translator or somethink
ok disregard my last question then
how do they know that g(x) = f(x + 2) + 7 ?
it doesn't say that anywhere in the question
cause f(x) is x^2
so (x+2)^2 is clearly f(x+2)
$(x +2)^2 = (1x+2) (1x+2)$
TheMane3
$(1x+2) (1x+2) = x^2 + 4x + 4$
TheMane3
so wouldn't it be $f(x + 4x + 4)$?
TheMane3
but in (x + 2)^2 the degree isnt being directly distributed to x
so how can it be x^2
right
ahh
I'm so confused why do we have to use double angle identities?
like can't we just find the cos of an angle and then just multiply it times two?
Because if you get a cosine of 1, double that is 2, right?
yeah
But you can't get a cosine of double the angle that's 2, right?
Because cosine only goes up to 1.
oh yeah
oHHHHHHHHHHHHHHH
dang that actually makes sense
THANKSSSSSSSSSSSSSSSSSSSSSSSSS
No problem.
dang your smart lol
I want to say that I computated something incorrectly but cannot see any mistakes
Not sure where the difference between -17 and -34 (my answer) comes from
ait
wait
I think my error is I set it = 0 not = 17 or something along these lines
Would love if someone can confirm this for me
If you have two numbers and you add those two numbers than the numbers that you added have numbered the second number that has just been added due to the subtraction of the first number that was numbered by the first number.
true?
what
what
@alpine sable that’s right, your error is what you set it equal to.
the RHS should be (w - w_0)
@lilac raptor
are you are saying if a + b = c,
Then b = c - a?
Thanks!
whats the best textbook for practice questions for calc I and II?
didnt even see that channel, thanks!
How do you do this? I've looked at some examples and I don't get it 
How do you even do the base case? Do you sub in n, k = 1? Bc I saw some using n = 1 and k = 0, 1
Is this oaky so far?
How am I supposed to show that it's an integer?? The sum of two integers is an integer but that requires showing that n choose k and n choose (k-1) are also integers, which is what I'm trying to do 
your statement is P(n): n choose k is an integer for k where 0<= k <= n
You use a strong hypothesis keep in mind
prove P(1) to be true. Assume P(i) is true and deduce P(i+1) gg 
you did the n=1 case, then assume it holds for n=j, then show n=j+1 is true
hey
$\binom{j+1}{k}=\binom{j}{k-1}+\binom{j}{k}$
i got a calc question
Mosh
the 2 co-efficients on the RHS are integers by the hypothesis, and sum of integers is an integer
Wait I'm an idiot LOL by "by the hypothesis" you mean the part where I say "assume it holds for n = j" right?
You need a strong hypothesis, so $\binom{j}{k}\in\mathbb{Z}, 0\leq k\leq j$
Mosh
That's what I did here right?
yes
yeah it's just 2 lines
yeah
Sweet, thanks Mosh
@obsidian marsh What's the domain of e^t?
,w Table[N[5(1 - e^(-5000t))], {t, 0, 25000, 2500}]
Looks like you should be looking around y = 5 or so.
,w Plot[5(1 - E^(-5000x)), {x, 0, 25000}]
@obsidian marsh ^
had this come up in a test the other day and everyone failed to get it right
I'm wondering how to go about solving this
bro what is that im definitely not qualified in the slightest to do that
Well notice that
$$\int_{-\infty}^\infty \frac{\dd{x}}{1+4\pi^2(x-5000)^2} = \int_{-\infty}^\infty \frac{\dd{x}}{1+[2\pi(x-5000)]^2}$$
Then do the substitution $u=2\pi(x-5000)$, $\dd{u}=2\pi \dd{x}$, so you have
$$\frac{1}{2\pi} \int_{-\infty}^\infty \frac{\dd{u}}{1+u^2}$$
From there you should probably be able to do it yourself
Lorago
ok?
Does that make sense?
yup thank you
Np
why does the answer take the reciprocal of tan?
the description even says that since (3pi/2 + theta) is in the 4th quadrant so shouldn't it be -tan?
@strong crater Because tangent is the slope of an angle. When you add 3/2 pi to an angle, it's perpendicular to the original angle. What happens to the slope when you find the perpendicular slope?
If the original slope is m, what's the perpendicular slope?
-1/m
Right, so if the original slope is tan(theta), the perpendicular slope is -1/tan(theta).
No problem.
i have a question about using the standard normal probabilities table. I have to look up the probability that : P(-1.72 < Z < 1.22) , and im not sure how to go about doing this. I thought that you subtract (1.22 - [-1.72]) and then look up the answer in the table but that was wrong.. any help?
<@&286206848099549185>
ight
16 should be fine
cause its 4 + 4
no negative numbers
so
[0, infinity)
sqrtx can never be -4
unless imaginary
so u said sqrtx + 4 =/ 0
that will always be true
since the sqrt of a pos number
is always positive
the only issue comes when x < 0
which you mentioned
ok, so the +4 ensures it'll never be 0
yes
yes
well
both of them?
so x - 2 / x + 4?
or just 1
both and just 1 if you dont mind explaining the diff
okay so
if both
then its for all x but x = -4
cause thenu have -6/0
vertical asymptote
if sqrt on top but not bottom
[0, infinity)
if just on top
same thing as well
sure thing 🤘
Does theorem corresponding to the last line have a name?
$$
\begin{equation}
\begin{cases}
f: X \to Y; \
g: Y \to Z; \
f^{\rightarrow}(S_x) = { y \in Y : \exists x \in S_x. y=f(x) } \
g^{\leftarrow} = { z \in Z: \exists y \in Y. z=g(y) } \
[g \circ f]^{\rightarrow}(S_x) = { z \in Z: \exists y \in f^{\rightarrow}(S_x) \cap g^{\leftarrow}. z=g(y) } \
[g \circ f]^{\rightarrow}(S_x) = [g_{\vert f^{\rightarrow}(S_x) \cap g^{\leftarrow}} \circ f^{\vert f^{\rightarrow}(S_x) \cap g^{\leftarrow}}]
\end{cases}
\end{equation}
$$
Note: $g_{\vert S_y}$ is domain restriction of $g$ to $S_y$ while $f^{\vert S_x}$ is corestriction of $f$ to $S_y$. I.e.
$$
\begin{equation}
\begin{cases}
f^{\vert S_y}: X \to S_y \
g_{\vert S_y}: S_y \to Z
\end{cases}
\end{equation}
$$
JohnDark
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Note: $g_{\vert S_y}$ is domain restriction of $g$ to $S_y$ while $f^{\vert S_y}$ is corestriction of $f$ to $S_y$. I.e.
$$
\begin{equation}
\begin{cases}
f^{\vert S_y}: X \to S_y \
g_{\vert S_y}: S_y \to Z
\end{cases}
\end{equation}
$$
JohnDark
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
can I get some help on this?
oooh i did this exat problem
lemme see
so what ive done so far is find the coordinates of B
we also know the x and y intercepts of the line
im confused where to go from here
or if im even on the right track
u gotta find the slope between A and B
the x intercept is C
u gotta find C as a function of r
show me what u got
one sec let me try and do it on paper this time
Please, don't break rules next time.
- Before asking a question, make sure that the channel you are using is not currently in use. An occupied channel would generally have an ongoing discussion or a trailing unanswered question. Likewise, when you are done using a channel, make this clear so that it's open for others to use.
nobody had typed in 20 min
so like 🤷♂️
Indeed, my bad
there are other open channels, and 20 minutes isn't that long
plus they'd already posted in precalc
i mean no one typed that they were done using this channel
and like the other guy said no one had typed for a while
yeah gimmie sec still doing some work
@slate monolith Where would you suggest me post the question that I posted here earlier? It is about function composition, domain restrictions and corestrictions. The topic of function composition is at basic level is covered in Intermediate algebra course here (https://www.mesacc.edu/~scotz47781/mat120/), but I'm unsure to which branch of mathematics it actually belongs because functions and their compositions are ubiquitous.
if I understand what youre saying, this isnt linear algebra, and prealgebra might not be so helpful so this is a good spot
maybe in questions-1
I'll copy the question from here to there, thank you! @slate monolith
np
so should I be trying to find the equation of the line first?
yes yes
find the slope between A and B
intrecept is A
$m=\frac{r-sqrt\left(r^2-\frac{r^4}{4}\right)}{-\frac{r^2}{2}}?$
Pahul's Uncle
that what im getting for slope lol
not simplified but yeah i think im doing it wrong
thats what i got too
um
ur syntax is confusing me
usually do the greater x first
so (x-1)^2 + y^2 - 1 = x^2 + y^2 - r^2
-2x = - r^2
x = r^2/2
so
this gets messy
wait, doesnt x = $r^2/2$
r^2/2 + y^2 = r^2
mchen10
mb mb+
yeah got that
looks good
👍
and we know the y intercept is r
pls help @here
An easy way to do this is to pick a point (or probably several) on the given graph look at its slope then plug in that point(s) into each of the choices and see if it matches
oki lemme try thx
ideally check the 0 values first
see if as u change x or y its constant or changing
or inc/decreasing
Yes. Try this.
And find a point where you can easy find the derivative visually.
how do i do this @here
yea thx i got it
Is this an exam? It sais 1 mark
could be hw
dont ping here or anything
dont ping anyone unless u waited 15 min for helper
srry m8
yea its a vce past paper
2020
tech free
ah
is this calc @crystal tapir
so from what i understand
g'(x) = 2x
so g = x^2
@here is disabled by the way, just post your question and if it doesnt get answered for 15 mins you can ping helpers
mhm
arent vce marking guides all available online?
yeah the marking guide for this exam is here https://www.vcaa.vic.edu.au/assessment/vce-assessment/past-examinations/Pages/Mathematical-Methods.aspx
in case you need help on any other questions in future
oh this doesnt give working though since its one mark
nvm
yea but it doesnt show working
ermm why
read above
Find all values of $x$ such that
$$\frac{x^2 + x + 3}{2x^2 + x - 6} \ge 0.$$
Note: Your solution should be thorough, and explain why all your values are the only values that satisfy the inequality.
MathMemer
writing problem for aops
whats ur question
@rugged bronze what have you done so far?
"A group of 4 students went to drink pearl tea and study at a local tea shop. The shop offers 12 different flavors of pearl tea. What is the probability that at least 2 students ordered the same flavor? Express your answer as a decimal, and round to the nearest ten thousandths."
May anyone explain this question please? It's on my Algebra 2 quiz and I'm really stressing out about it
One minus they all pick a different tea. 1 - [(1/12) * (1/11) * (1/10) * (1/9)]
S = {all different, at least two}. So 1 - P(all different) = P(atleast two)
note: 'at least 2' contains many more combinations, but in this case we do not have to worry about enumerating them.
e.g. 'exactly 3' is in 'at least 2'.
what i dont think it would be that high
yay, it will be high. because it includes at least 3 + at least 4 + exactly 3 + exactly 4.
meaning, at least 2 also includes they all order the same tea, etc
probably not about 99.99% as answer tho
maybe its actually 1 - [(12/12) * (11/12) * (10/12) * (9/12)]

I wanted to prove that the top compound proposition is a tautology by using logical equivalences. Does my work look correct here? (CDE = conditional-disjunction equivalence here)
Yes.
yay. those things take forever.
Every time I made a tiny error and had to scrap and start from scratch
I remember have to prove +0 = -0. it was like 4 lines and it took me about 4 hours to build.
I'm always amazed at how much working on problems helps solidify. Every time I think about being lazy and skipping the exercises, I remember how valuable they are
😮 that sounds way harder lol
oh alright, then the probability would be equivalent to <0.4721
seriously the last rule of this server is kinda pointless
i mean, it kinda makes you think... my major my choices lmao
hey guys ive been working on this question for robotics for the past few hours
from what i remember, i need to use the lagrangian, except im not fully sure how to do it
